/* Parser accelerator module *//* The parser as originally conceived had disappointing performance. This module does some precomputation that speeds up the selection of a DFA based upon a token, turning a search through an array into a simple indexing operation. The parser now cannot work without the accelerators installed. Note that the accelerators are installed dynamically when the parser is initialized, they are not part of the static data structure written on graminit.[ch] by the parser generator. */#include "pgenheaders.h"#include "grammar.h"#include "node.h"#include "token.h"#include "parser.h"/* Forward references */staticvoidfixdfa(grammar*,dfa*);staticvoidfixstate(grammar*,state*);voidPyGrammar_AddAccelerators(grammar*g){dfa*d;inti;d=g->g_dfa;for(i=g->g_ndfas;--i>=0;d++)fixdfa(g,d);g->g_accel=1;}voidPyGrammar_RemoveAccelerators(grammar*g){dfa*d;inti;g->g_accel=0;d=g->g_dfa;for(i=g->g_ndfas;--i>=0;d++){state*s;intj;s=d->d_state;for(j=0;j<d->d_nstates;j++,s++){if(s->s_accel)PyObject_FREE(s->s_accel);s->s_accel=NULL;}}}staticvoidfixdfa(grammar*g,dfa*d){state*s;intj;s=d->d_state;for(j=0;j<d->d_nstates;j++,s++)fixstate(g,s);}staticvoidfixstate(grammar*g,state*s){arc*a;intk;int*accel;intnl=g->g_ll.ll_nlabels;s->s_accept=0;accel=(int*)PyObject_MALLOC(nl*sizeof(int));if(accel==NULL){fprintf(stderr,"no mem to build parser accelerators\n");exit(1);}for(k=0;k<nl;k++)accel[k]=-1;a=s->s_arc;for(k=s->s_narcs;--k>=0;a++){intlbl=a->a_lbl;label*l=&g->g_ll.ll_label[lbl];inttype=l->lb_type;if(a->a_arrow>=(1<<7)){printf("XXX too many states!\n");continue;}if(ISNONTERMINAL(type)){dfa*d1=PyGrammar_FindDFA(g,type);intibit;if(type-NT_OFFSET>=(1<<7)){printf("XXX too high nonterminal number!\n");continue;}for(ibit=0;ibit<g->g_ll.ll_nlabels;ibit++){if(testbit(d1->d_first,ibit)){if(accel[ibit]!=-1)printf("XXX ambiguity!\n");accel[ibit]=a->a_arrow|(1<<7)|((type-NT_OFFSET)<<8);}}}elseif(lbl==EMPTY)s->s_accept=1;elseif(lbl>=0&&lbl<nl)accel[lbl]=a->a_arrow;}while(nl>0&&accel[nl-1]==-1)nl--;for(k=0;k<nl&&accel[k]==-1;)k++;if(k<nl){inti;s->s_accel=(int*)PyObject_MALLOC((nl-k)*sizeof(int));if(s->s_accel==NULL){fprintf(stderr,"no mem to add parser accelerators\n");exit(1);}s->s_lower=k;s->s_upper=nl;for(i=0;k<nl;i++,k++)s->s_accel[i]=accel[k];}PyObject_FREE(accel);}